Rigid polyvinyl chloride (PVC) products such as building panels, e.g. siding and roofing panels, are frequently coated with top coats designed to enhance the decorative effect of the products or to protect the products from weathering. Such PVC products frequently include in the PVC compositions minor amounts of lubricants to enable the article to be extruded or calendered to the desired shape. Unfortunately, many of the lubricant compositions commonly used, especially metallic soap of higher fatty acids, when used in amounts sufficient to impart the desired lubricating properties to the PVC composition, have a tendency to exude from the surface of the finished product. This substantially reduces the ability of most commonly used top coats to adhere to the surface of the article and causes a whitening of the surface. While solvents have been satisfactorily used in preparing the surfaces or rigid PVC substrates for application of top coats, the use of solvents is generally considered undesirable because of the cost and health hazards associated with solvent vapors. The use of solvents for this purpose also usually necessitates a delay of up to several weeks between formation of the PVC substrate and the solvent treatment to prevent further exudation of lubricant after cleaning of the substrate with solvent.